This thesis studies the educational effect of the two-way immersion dual language programs (DLE) in California’s public elementary school system using statewide testing scores as the common measurement tool. The average California Test Standards (CTS) test scores for English language arts (ELA), Mathematics and Science on the California statewide assessment, STAR, for 5th graders in the years 2009-2012, were utilize to compare student achievement for dual language participants to students in similar schools. Similar schools are matched to the participating schools by the state assigned schools ranking.

This study evaluated DLE programs in terms of academic achievement and its effect on minimize the achievement gap between English learners (ELL) and English speakers (ES). The analysis consists of a series of OLS regression models that evaluates test scores on a series of variables that can help the state government assess quality of education received by DLE participants. I found a highly statistically significant correlation between ES’s achievement level and DLE participation, this relationship was consistent even when I considered scores from the far right tail of the achievement distribution. A positive but not statistically significant correlation was found for ELL in the participating schools. It should be noted that in this study, only those student who had yet to be identified as English proficient were considered under the ELL subgroup. Therefore, the end of the year examination might be testing language proficiency more than academic achievement. Nevertheless, DLE was found to be positive for all regressions.